Identifying and Fixing power bugs in Android Apps

1. Understanding, Debugging and Fixing
Power Bugs
Aditya & Satyam

2. Apps are to blame the most for bad battery
life
Power Bugs

3. • Bad coding patterns cause power bugs
• Specific behaviors of the Android Platform
• App inter-dependencies!
• Special Attention must be paid to optimize
for power!
Power Bugs

4. Users Hate Power Bugs

5. Understanding Common
Power Bugs

6. Common Power Bugs
1. Not Sleeping Properly

7. Common Power Bugs
2. Un-necessary Animations

8. Common Power Bugs
3. Updating the Screen

9. Common Power Bugs
4. Handling Display-Off

10. Common Power Bugs
5. Waking up to notifications

11. • Registering for un-necessary events
• Waking up the system causes everyone to
be woken up
• Register for “active” notifications (instead
of passive ones)
• Handset-specific problems
More Types Of Power Bugs

12. Best Practices
(or how to avoid the dreaded battery drain)

13. Jeff Sharkey at Google IO
Power Consumption is Complex and Inter-dependent
among components

14. • prefetch data
– to avoid switching states frequently, try and read as
much data as possible
– trade-off between too much pre-fetch and battery
drain
– google recommends pre-fetching data that you will
initiate in the next 2 to 5 minutes, and in the order of
1-5 MB size
• batch data
– do data send/receive in batches rather than on-
demand
Best Practices - Network
– eg: batch analytics information, rather than sending
them as they are collected

15. • using inexact timers
– AlarmManager.setInexactRepeating()
– use ELAPSED_REALTIME instead of
ELAPSED_REALTIME_WAKEUP
• detect network connection
– avoid connection attempts if no network is active
• avoid polling and use GCM when possible
– avoids multiple connections
– reduces the number of device state changes
Best Practices - Network

16. • color matters!
– esp on OLED
screens
– darker the color,
lesser the
consumption
• brightness levels
have more impact
– refer to -
http://stackoverflow.com/qu
estions/5032588/cant-
apply-system-screen-
brightness-
programmatically-in-
android
Best Practices - Screen

17. • programmatically
reduce brightness
if its suits your
app/activity
• Use “night mode”
for reading Apps
• Think about your
color scheme
Best Practices - Screen

18. • wakelocks are your
friend, but your users
worst nightmare!
• use them only if really
needed and ensure they
are removed as soon as
possible
• Use
‘android:keepScreenOn’
property in your manifest
instead of doing it
programmatically
Best Practices - CPU

19. • if possible, spread out
your computationally
intensive job
• gpu typically consumes
more power than cpu
– avoid floating point math
where possible
• use algorithms that
consume less CPU cycle
– O(n log n) vs O(n 2)
algorithms
Best Practices - CPU

20. Demo
Identifying power bugs with
little eye

21. Optimized Apps = Better User Experience
Thank You
www.littleeye.co
aditya@littleeye.co
satyam@littleeye.co